Sorry about that. I had no idea iplayer was not available outside the UK.
Basically she sings The Brean Lament which is about sailors lost in the Severn Estury between Wales and the south west of England. I found it quite poignant as she delivers it both from the shore at Brean and from inside a church.
The programme (and herself) talk about the 15 meter tides and the (locally) well known vagaries of the tides and rips causing bodies to be washed out and returned, and of unknown sailors being washed up and given a burial outside the wall of the church. The reason? Apparently people believed that the sea might reclaim the bodies and they did not want villagers bodies being taken with them. It was custom to bury the footwear of victims below the tide line in the hope that that would satisfy the seas need to reclaim what was washed ashore.
The sea reclaiming might sound fanciful, but the Severn Estury did have (not mentioned in the show) a Tsunami (in the 1600's) that, amongst other things churned up some burials?
As I said, sorry, as the hearing and seeing is better than the telling!